Electric brake



(No Model.) v

W. B. POTTER.

.ELECTRIC BRAKE.

NQ. 542,309. Patented Ju-lyvQ, 1895 UNITED' STATES- PATENTV- OFFICE.

WILLTAM E. POTTER, OE sCHENECTADY, NEW YORK, ASSIGNOR To THE GENERALELECTRIC COMPANY, OE NEW YORK.

ELECTRIC BRAKE.

SPECIFICATION forming part of Letters Patent No. 542,309, dated July 9,1895. Application filed March 20, 18.95. Serial No. 542,492. (No model.)

To all whom it may concern:

Be it known that I, WILLIAM B. POTTER, a citizen of the United States,residingat Schenectady, in thecounty of Schenectady and State of NewYork, have invented certain new and `useful Improvements in ElectricBrakes, of

which the following is a specification.

My invention relates to electric brakes, particularly to the class ofbrakes in which the shoe is applied directly to the tread of the wheel;and it has for its object to so arrange the apparatus that the ordinaryhand-brake may be effectually applied, and by means' of the sameapparatus electric power may be used, either for emergency or as aregular means of stopping the train, with the handbrake held in reserve.

It has been found desirable (with some classes of traffic) to apply theshoe directly to the tread of the wheel and thereby maintain lthe shapeof the tread unaffected by the Wear of the rail, at the same timepreserving the ooncentricity of the wheel. In the application of theelectric brake to such shoes it is found that they do not presentsuliicient bearing-surface for the best effect electrically. It .istherefore impracticable, ordinarily, to use thesame brake-shoe forapplication by hand and by power, it having been found that only acertain arc of the wheel may be covered by the shoe when applied byhand. If any greater arc be embraced the shoe will chatter on the wheeland be inelfective in stopping it, as well as noisy and' liable to causeaccident by its vibration. On the other handv there is no practicallimit to the arc of the shoe, which may be l applied'by electricalpower, inasmuch as the one ofwhich is applied by hand and both or anynumber of which are applied by the elec- 'by the momentum of the car.

tric power; or I may provide shoes a portion of each of which will beapplied by hand and' the whole applied by electric power; or I maycombine `the two in one apparatus. `All of these different forms will bewithin my invention. A

My invention further consists in certain details of constructionhereinafter pointed out and specifically claimed.

The accompanying drawings show an application of my invention to onewheel of an ordinarytruck, which may represent a tramwaycar or one wheelof a train. Itis of course to be understood that equivalent apparatus isapplied to the other wheels, and necessarily Iv do not limit myself to asingle truck of the class described. 4In the drawings, Figure l is aside elevation, partlyin section,ofone wheel ofa carequipped with myimproved brake. Fig. 2 is a plan, also partly in section, of some of theparts shown in Fig. 1. Figs. 3 and -1 are side ele.- vations ofmoditiedforms of shoe. l

Referring by letter, A is the truck-frame, which may be of any suitableor appropriate form. B is the ordinary pedestal. C is the wheel, ofwhich D is the axle. E is the electric motor of the now well-knownironclad 'or Waterproof type. All of these parts are old and well knownin the art.

F is my improved electric brake, 'G being the core of the yoke-piece,surrounded by the coil H, serving to energize it. By preference the coilis energized from the current derived from the motor used as agenerator, after the trolley-current has been out off and the motorreversed in the ordinary way, it being driven Any other source ofelectric current may be substituted, however, aspthis particulararrangement is not a limiting feature of`my invention. In

lthe particular form shown in Figs. l and 2 l attach to the ends ofthe'core or yoke-piece G brake-shoes I I', forming pole-pieces for themagnet, which, when energized, are strongly IOO this one of the shoes Ihave selected for application by hand. The means for so applying theshoe are best seen in Fig. 2, in which M is the hand brake-rod and M thebrakelever pivoted at- M2 to the brake-beam M3.

Referring again to Fig. 1, the shoe I is pivoted at t" to the yoke. Theposition of this shoe is such as to necessitate some mechanical meansfor preventing its tipping over against the Wheel. This is shown at I2,and

consists of a projecting lug from the yokepiece G, against which thelower part of the shoe may bear.

The entire apparatus is hung on a link or links K, and its play to andfrom the wheel is limited by the stop O, aiixed to any appropriate partof the truck-frame.

In order to maintain the brakeshoe I as close to the tread of the wheelas possible without touching it, I employ the stop N, reaching from thebearing L of themotor to the brake-beam M3. This stop N consists of abar engaging with the brake-beam loosely and secured by the pin N' in aslot in the bearing at a point as near as possible to the axle D. Thestop thus becomes independent of any lost motion in the truck, the brakebeam moving coincidently with the axle, and therefore thebrake-shoe Imay, by properly choosing the length of the stop-bar N, be held at justthe desired distance.` It is of course essential for the application ofthe shoe as an electric brake that the air-gap be as small as possible,and some form of stop is therefore essential.

The modified forms of shoe shown in Figs. 3 and 4 provide in a singleshoe the two contact portions required for application as a hand-brakeand as an electric brake. In these the reference-letters refer to thesame parts; but in Fig. 3 the tread of the brake-shoe is provided withprojections I4 l, engaging with the wheel, and only this part of theshoe is effective in stopping the wheel when applied by hand. Vhen theelectric current., however, is used, then the parts I5 I5 of the shoealso become energized, and act by a magnetic f attraction to greatlyincrease the pressure upon the parts I4 I4, at the same time affording amagnetic resistance to the rotation of the wheel. In Fig. 4 the part I3of the shoe is hinged at Ai2 to the part I, and this, when the shoe isapplied by hand, does not touch the wheel C, but when the coil I-I isenergized this part I3 becomes a part of the pole-piece of the for thehand-brake than that employed for the electric brake, and it is thisprinciple which forms the essence of my invention.

What I claim as new, and desire to secure by Letters Patent of theUnited States, is-

1;* In a braking apparatus and in combination, a wheel or other movingelement, of the driven apparatus and a part co-operating therewith inarresting its motion, such part having a plurality of portionsco-operating with and acting tostop the Wheel, some only of which areactuated manually, and all of which may be actuated by power.

2. In a braking apparatus and in combination, a brake shoe normallyengaging with a wheel or moving element when manually actuated, andhaving then a certain area of engagement, but co-operating with themoving element over a greater area when actuated by power.

3. In combination, in a braking apparatus, a wheel or moving element, abrake shoe or similar retarding means, manually actuated means forapplying such shoe, such manually actuated means operating a part onlyof such shoe, and a power actuated mechanism connected with the entireshoe or retarding means, and applying the whole of it to the wheel.

' 4. In combination, in a braking apparatus, a wheel or moving element,a brake shoe or similar retarding means (zo-operating therewith, meansfor manually actuating the shoe, Such means engaging with a part only ofthe shoe, an electric circuit, a source of power for such circuit, andmeans, actuated by the current from such source of power, for applyingthe entire shoe to the wheel or moving element.

5. In a braking apparatus, and in combination, a wheel or movingelement, a brake shoe co-operating therewith in arresting its motion,means for manually actuating a part of the brake shoe, means forelectrically actuating the entire shoe, and a stop preserving the relation of 'the shoe to the axle of the wheel; whereby the shoe may bemaintained as close as desired to the tread of the wheel.

6. In a braking apparatus and in combination, a wheel or moving element,a brake shoe, means for manually applying part of the brake shoe to thewheel, an electric motorV driving the wheel, and means, actuated by thecurrent from the motor, for electrically applying the entire shoe to thewheel.

In witness whereof I have hereunto set my hand this 19th day of March,1895.

WILLIAM B. POTTER.

Witnesses:

Y B. B. HULL,

A. F. MACDONALD.

ICC

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